Process of treating lamps



Nov. 9, 1937. F, A LU 2,098,582

PROCESS OF TREATING LAMPS Filed June 4, 1936 INVENTOR M ATTORNEY Patented Nov. 9, 1937 UNITED STATES PATENT OFFICE 2,098,582 PROCESS OF TREATING LAMPS Frederick Kallus, Hoboken, N. J. Application June 4, 1936, Serial No. 83,445

3 Claims.

This invention relates to methods.of etching 4 and tempering frosted glass bulbs.

It is an object of thisinyention to devise a process by which glass bulbs may be frosted upon 5 the interior and may be so tempered and relieved of internal strains, that they are suitable for use in manufacture of electric lamps without undue breakage.

When bulbs intended for electric lamps are frosted upon the inside by fluorine containing solution and then washed, the resultant product may become brittle and unsatisfactory for commercial use. Various processes have been devised to etch such bulbs without leaving them in this brittle condition, but such processes have not been wholly satisfactory. When a bulb is etched upon its interior with fluorine and immediately washed in water, this brittleness is apparently accentuated. It is by no means clear to what, the fragility of the normally etched bulbs is due, and explanations have been offered and in part accepted, but it is doubtful that they are in accordance with all of the facts. It has been customary, therefore, to subject the freshly etched bulb with a dilute solution of the etching fluid,

a process commonly referred to as fortifying,

which is represented as rounding out the sharp edges in the glass and so strengthen the bulb.

in accordance with this invention, has been found that burns can be etched with .fluorine without producing this brittleness and without fortifying, by-annealing the bulb after the etching process accordingly, the bulb, after being etched with fluorine, is subjected imme- 35 diately'to an internal bath of super-saturated steam. l I

By this process a bulb can be formed which, withoutany fortifyingprocess whatsoever, is free from any internal strainsand has substantially the same strength as an unetched bulb. The causes of this result are not easily traced. It

seems probable, however that thestrains incident to theetching are the resultof products of chemical reaction resulting from the effect of the 45 iiuorineupon the glass, which products create unequal surface effects upon the glass and imp'ose unequal strains internally. This process relieves the bulb both by dissolving off the undesired products of reaction by'the super-saturated steam, andat the same time by reason of the heat of the steam, anneals the internal strains,

which have been set up. There is much to support this explanation because the use of water is 55 notLlielpful in relieving the strains and even ap however, it

pears to accentuate them, whereas they are completely relieved by the steam.

In the drawing there is illustrated an apparatus for carrying out this invention in which the numeral l designates a tank adapted to contain 5 water as shown at 2 and having immersed with-' in it a steam pipe 3 having perforations 4, the steam being controlled by a valve 5. The tank I may be provided with a water gage 6 for control of the level of the water within the tank. 10 Within the upper portion of the tank there is provided a water pipe 1 having a control valve 8. This pipe extends throughout the length of the tank I!) provided-with a series of uprights 9 at spaced intervals to extend upwardly within the 15 bulbs to be treated as will hereinafter be described. The pipes 9 are preferably smaller in diameter than the pipe I so that the water will issue from the outlets in the form of a jet. The bulbs l0 are inverted over hollow posts II in a 20 tray l2 adapted to be removably fitted within the top of the tank I, the hollow posts ll being so disposed that each will encircle one of the upright pipes 9. A bracket l3 may be provided surrounding each of the posts II to receive the 25 bottom portion of the bulb and the tray l2 has a discharge opening 14. In carrying out this process the bulbs are inverted upon the posts I l as shown, and etched with the fluorine in the usual manner. Thereupon, the tray carrying the etched bulbs is brought to and inserted in the tank I with one of the pipes 9 extending upwardly into each bulb. Thereupon the steam is emitted through the valve 5, and bubbling up through the water becomes super-saturated and issues through the posts ll around the water pipes 9 into theinterior of the bulb. Here it reacts upon the bulb and contents, passing out through openings IS in the bracket l3 into the tray l2, and hence out through the discharge i4. After the steam is passed out for about seven seconds, the water may be turned on through the valve 8 to wash out the products of reaction between the steam, the glass, and the fluorine solution previously used. Thereafter the bulbs may 5 be dried and are ready for fabrication into lamps.

Experience has shown that this process of operation permits the etching of lamps without making them fragile and hence renders unnnecessary any process of fortifying, such as has heretofore been deemed essential.

Since certain changes may be made in carrying out the above method without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of theinvention which, as a matter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secure by Letters Patent, is:-

1. A process of treating bulbs which comprises subjecting them to an etching fluid upon the interior and subsequently treating them to the mixture which is formed by blowing steam through a hot water bath.

2. A process of treating bulbs which comprises subjecting them to an etching fluid upon the interior and subsequently treating them to the mixture which is formed by blowing steam through a hot water bath for a period of about seven seconds.

3. A process of treating bulbs which comprises subjecting them to an etching fluid upon the interior and subsequently treating them to the mixture which is formed by blowing steam through a hot water bath for a period of about seven seconds and then washing them with water.

FREDERICK KALLUS. 

